The objectives of this proposal are to identify the regulatory mechanisms through which ACTH controls adrenal cortical metabolism. Toward this end a study of a family of cAMP-binding proteins (two of which are increased in concentration by ACTH) is being made. The subcellular localization of these proteins is being examined by photoaffinity labelling and conventional subcellular fractionation techniques. They are being isolated by affinity chromatography and characterized by polyacrylamide gel electrophoresis and isoelectric focusing polyacrylamide gel electrophoresis. Their function will be studied by determining their relationship to protein kinases and phosphodiesterases and by examining their effects on cholesterol transport to mitochondrial P450scc and upon the catalytic activity of this enzyme.